January 19th, 2006
|12:56 pm - Cooperation, aggression, and primates|
Here's an absolutely fascinating article on aggression, cooperation, and social structure among primates. I'm especially pleased because the evidence in it comes down quite firmly against genetic determinism of social behavior, in ways that quite surprised me, one of the more striking examples is:
The second experiment was set up by de Waal and his student Denise Johanowicz in the early 1990s, working with two macaque monkey species. By any human standards, male rhesus macaques are unappealing animals. Their hierarchies are rigid, those at the top seize a disproportionate share of the spoils, they enforce this inequity with ferocious aggression, and they rarely reconcile after fights. Male stump tail macaques, in contrast, which share almost all of their genes with their rhesus macaque cousins, display much less aggression, more affiliative behaviors, looser hierarchies, and more egalitarianism. The incident with baboons described immediate after this is equally impressive.
Working with captive primates, de Waal and Johanowicz created a mixed-sex social group of juvenile macaques, combining rhesus and stump tails together. Remarkably, instead of the rhesus macaques bullying the stump tails, over the course of a few months, the rhesus males adopted the stump tails' social style, eventually even matching the stump tails' high rates of reconciliatory behavior. It so happens, moreover, that stump tails and rhesus macaques use different gestures when reconciling. The rhesus macaques in the study did not start using the stump tails' reconciliatory gestures, but rather increased the incidence of their own species-typical gestures. In other words, they were not merely imitating the stump tails' behavior; they were incorporating the concept of frequent reconciliation into their own social practices. When the newly warm-and-fuzzy rhesus macaques were returned to a larger, all-rhesus group, finally, their new behavioral style persisted.
This is nothing short of extraordinary. But it brings up one last question: When those rhesus macaques were transferred back into the all-rhesus world, did they spread their insights and behaviors to the others? Alas, they did not. For that, we need to move on to our final case.
Also, as many studies have shown, we are equally plastic beings, I've run across the following information before:
In exploring these subjects, one often encounters a pessimism built around the notion that humans, as primates, are hard-wired for xenophobia. Some brain-imaging studies have appeared to support this view in a particularly discouraging way. There is a structure deep inside the brain called the amygdala, which plays a key role in fear and aggression, and experiments have shown that when subjects are presented with a face of someone from a different race, the amygdala gets metabolically active -- aroused, alert, ready for action. This happens even when the face is presented "subliminally," which is to say, so rapidly that the subject does not consciously see it. Moreover, the most recent data that I've seen indicates that such responses can change quite rapidly if the individual is exposed to the correct stimulus. In any case, we like other primates once again prove to be exceedingly malleable and once again the genetic component of human behavior (especially) social behavior is shown to be at best minimal.
More recent studies, however, should mitigate this pessimism. Test a person who has a lot of experience with people of different races, and the amygdala does not activate. Or, as in a wonderful experiment by Susan Fiske, of Princeton University, subtly bias the subject beforehand to think of people as individuals rather than as members of a group, and the amygdala does not budge. Humans may be hard-wired to get edgy around the Other, but our views on who falls into that category are decidedly malleable.
Current Mood: pleased
That article put a big smile on my face (most things that empower humans to perceive themselves as willed beings & hopefully behave accordingly make me smile)
I love Frans de Waal! His book The Ape and the Sushi Master: Cultural Reflections of a Primatologist is completely amazing.